Add /api/v1/admin/domain_blocks (#18247)

* Add /api/v1/admin/domain_blocks

Fixes #18140

- `GET /api/v1/admin/domain_blocks` lists domain blocks
- `GET /api/v1/admin/domain_blocks/:id` shows one by ID
- `DELETE /api/v1/admin/domain_blocks/:id` deletes a given domain block
- `POST /api/v1/admin/domain_blocks` to create a new domain block:
  if it conflicts with an existing one, returns an error with
  an attribute `existing_domain_block` with the rendered domain block

* Simplify conflict handling as suggested in review

1 files changed, 109 insertions, 0 deletions

diff --git a/app/controllers/api/v1/admin/domain_blocks_controller.rb b/app/controllers/api/v1/admin/domain_blocks_controller.rb
new file mode 100644
index 000000000..229870eee
--- /dev/null
+++ b/app/controllers/api/v1/admin/domain_blocks_controller.rb
@@ -0,0 +1,109 @@
+# frozen_string_literal: true
+
+class Api::V1::Admin::DomainBlocksController < Api::BaseController
+  include Authorization
+  include AccountableConcern
+
+  LIMIT = 100
+
+  before_action -> { authorize_if_got_token! :'admin:read', :'admin:read:domain_blocks' }, only: [:index, :show]
+  before_action -> { authorize_if_got_token! :'admin:write', :'admin:write:domain_blocks' }, except: [:index, :show]
+  before_action :require_staff!
+  before_action :set_domain_blocks, only: :index
+  before_action :set_domain_block, only: [:show, :update, :destroy]
+
+  after_action :insert_pagination_headers, only: :index
+
+  PAGINATION_PARAMS = %i(limit).freeze
+
+  def create
+    authorize :domain_block, :create?
+
+    existing_domain_block = resource_params[:domain].present? ? DomainBlock.rule_for(resource_params[:domain]) : nil
+    return render json: existing_domain_block, serializer: REST::Admin::ExistingDomainBlockErrorSerializer, status: 422 if existing_domain_block.present?
+
+    @domain_block = DomainBlock.create!(resource_params)
+    DomainBlockWorker.perform_async(@domain_block.id)
+    log_action :create, @domain_block
+    render json: @domain_block, serializer: REST::Admin::DomainBlockSerializer
+  end
+
+  def index
+    authorize :domain_block, :index?
+    render json: @domain_blocks, each_serializer: REST::Admin::DomainBlockSerializer
+  end
+
+  def show
+    authorize @domain_block, :show?
+    render json: @domain_block, serializer: REST::Admin::DomainBlockSerializer
+  end
+
+  def update
+    authorize @domain_block, :update?
+
+    @domain_block.update(domain_block_params)
+    severity_changed = @domain_block.severity_changed?
+    @domain_block.save!
+    DomainBlockWorker.perform_async(@domain_block.id, severity_changed)
+    log_action :update, @domain_block
+    render json: @domain_block, serializer: REST::Admin::DomainBlockSerializer
+  end
+
+  def destroy
+    authorize @domain_block, :destroy?
+    UnblockDomainService.new.call(@domain_block)
+    log_action :destroy, @domain_block
+    render json: @domain_block, serializer: REST::Admin::DomainBlockSerializer
+  end
+
+  private
+
+  def set_domain_blocks
+    @domain_blocks = filtered_domain_blocks.order(id: :desc).to_a_paginated_by_id(limit_param(LIMIT), params_slice(:max_id, :since_id, :min_id))
+  end
+
+  def set_domain_block
+    @domain_block = DomainBlock.find(params[:id])
+  end
+
+  def filtered_domain_blocks
+    # TODO: no filtering yet
+    DomainBlock.all
+  end
+
+  def domain_block_params
+    params.permit(:severity, :reject_media, :reject_reports, :private_comment, :public_comment, :obfuscate)
+  end
+
+  def insert_pagination_headers
+    set_pagination_headers(next_path, prev_path)
+  end
+
+  def next_path
+    api_v1_admin_domain_blocks_url(pagination_params(max_id: pagination_max_id)) if records_continue?
+  end
+
+  def prev_path
+    api_v1_admin_domain_blocks_url(pagination_params(min_id: pagination_since_id)) unless @domain_blocks.empty?
+  end
+
+  def pagination_max_id
+    @domain_blocks.last.id
+  end
+
+  def pagination_since_id
+    @domain_blocks.first.id
+  end
+
+  def records_continue?
+    @domain_blocks.size == limit_param(LIMIT)
+  end
+
+  def pagination_params(core_params)
+    params.slice(*PAGINATION_PARAMS).permit(*PAGINATION_PARAMS).merge(core_params)
+  end
+
+  def resource_params
+    params.permit(:domain, :severity, :reject_media, :reject_reports, :private_comment, :public_comment, :obfuscate)
+  end
+end